My InterpretationHere is what this wonderful song means to me.
Now before anybody goes off, I do know Robert said its about aging.

My interpretation, is an everlasting, inescapable depression.

I am slowing down
As the years go by
I am sinking

This sounds like somebody is giving up. They're not doing with their life(hence slowing down). Depression could last years, but it could also feel like years, even if its a few days. And sinking, they're losing the battle of depression. They can't tread the water.

So I trick myself
Like everybody else

The secrets I hide
Twist me inside
They make me weaker

When people are depressed, they generally trick themselves into thinking they're happy. The secrets he hides is all the things that depress and upset him. They not only affect them physically, but emotionally as well.

I crouch in fear and wait
I'll never feel again...
If only I could remember
Anything at all

This sounds like sitting alone, thinking, wondering. Not believing they will feel anything other than the depression. They don't remember happiness, or good memories. The only thing on their mind is the depression.

Remember, this is MY person interpretation. I am in no way saying this is what the song is about.

General CommentThis is definitely one of my favourite Cure songs. The keyboards melody has a very "oceanic" feel which perfectly evokes the imagery of "sinking", and the music reaches a vivid climax towards the end. "I crouch in fear and wait" refers to each person's fear of their own mortality. "I trick myself" refers to how we disguise our fears by holding on to some faith (religion, etc). "If only I could remember" is also a very poignant line. It is sad to think that when we die we might not remember anything and we won't even remember that we ever existed. It relates to the existential notion of the absurdity of life.

General CommentTHIS WASA I THINK THE FIRST OF MANY SIMILAR CURE SONGS LIKE A THUOSAND HOURS AND SUCH THROUGH TO TRUTH GOODNESS BEAUTY IN A WAY.
NICE ONE FOR THE FIRST TRY TOO.
THE SHORT TO THER POINT SCHEME PLUS A LONG MUSICAL INTRO-OUTRO